FLP-mediated recombination between the FRT sites present in P{5'CXY21.29}X15 and P{3'CXY21.33}X15 has reconstituted a functional lacZ reporter, in which αTub84B promoter sequences drive expression of lacZ.
Used as marker for mosaic analysis in embryos.
Exists in clones, not reported as being germ-line transmitted.